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Ursell Arends
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Ursell is a surname. Notable people with the surname include: * Fritz Ursell (1923–2012), British mathematician * Geoffrey Ursell (1943–2021), Canadian writer * Harold Douglas Ursell (1907–1969), English mathematician See also * Pursell * Ursell function * Ursell number In fluid dynamics, the Ursell number indicates the nonlinearity of long surface gravity waves on a fluid layer. This dimensionless parameter is named after Fritz Ursell, who discussed its significance in 1953. The Ursell number is derived from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fritz Ursell
Fritz Joseph Ursell FRS (28 April 1923 – 11 May 2012) was a British mathematician noted for his contributions to fluid mechanics, especially in the area of wave-structure interactions. He held the Beyer Chair of Applied Mathematics at the University of Manchester from 1961 to 1990, was elected Fellow of the Royal Society in 1972 and retired in 1990. Education Ursell came to England as a Jewish refugee in 1937 from Germany. From 1941 to 1943 he studied at Trinity College, Cambridge, graduating with a bachelor degree in mathematics. Career At the end of 1943 Ursell joined the Admiralty as a part of a team—headed by George Deacon (not John Deacon) —whose task was to formulate rules for forecasting waves for the allied landings in Japan. Their findings have become the basis of modern wave-forecasting. Ursell stayed in the Admiralty until 1947. In 1947 he was appointed to a post-doctoral fellowship in applied mathematics at Manchester University without a doctorate. In 1950 he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geoffrey Ursell
Geoffrey Ursell (March 14, 1943 – February 21, 2021) ''Encyclopedia of Saskatchewan''. was a writer, who won the Books in Canada First Novel Award in 1985 for his novel ''Perdue, or How the West Was Lost''."Writer from Regina wins book award". '''', March 29, 1985. Career Predominantly known as a playwright, Ursell's stage and musical plays have included ''The Running of the Deer'' (1981), ''Saskatoon Pie' ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Douglas Ursell
Harold Douglas Ursell (1907–1969) was an English mathematician who is best known for Ursell function In statistical mechanics, an Ursell function or connected correlation function, is a cumulant of a random variable. It can often be obtained by summing over connected Feynman diagrams (the sum over all Feynman diagrams gives the correlation function .... References * 20th-century English mathematicians 1907 births 1969 deaths {{UK-mathematician-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pursell
Pursell is a surname. Notable people with the surname include: *Bill Pursell (1926–2020), American composer and former session pianist *Bob Pursell (footballer born 1889) (1889–1974), footballer * Bob Pursell (footballer born 1919) (1919–2005), Scottish footballer * Carl Pursell (1932–2009), politician from the U.S. state of Michigan *Isaac Pursell (1853–1910), Philadelphia, Pennsylvania-based architect *Peter Pursell (1894–1968), Scottish footballer See also *Purell Purell is an American brand of hand sanitizer invented in 1988, and introduced to the consumer market in 1997, by GOJO Industries. Its primary component is ethyl alcohol (70% v/v), and is used by wetting one's hands thoroughly with the product, ... * Ursell {{surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursell Function
In statistical mechanics, an Ursell function or connected correlation function, is a cumulant of a random variable. It can often be obtained by summing over connected Feynman diagrams (the sum over all Feynman diagrams gives the correlation functions). The Ursell function was named after Harold Ursell, who introduced it in 1927. Definition If ''X'' is a random variable, the moments ''s''''n'' and cumulants (same as the Ursell functions) ''u''''n'' are functions of ''X'' related by the exponential formula: : \operatorname(\exp(zX)) = \sum_n s_n \frac = \exp\left(\sum_n u_n \frac\right) (where \operatorname is the expectation). The Ursell functions for multivariate random variables are defined analogously to the above, and in the same way as multivariate cumulants. :u_n\left(X_1, \ldots, X_n\right) = \left.\frac \cdots \frac\log \operatorname\left(\exp\sum z_i X_i\right)\_ The Ursell functions of a single random variable ''X'' are obtained from these by setting . The first few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |